Breathing apparatus



Feb. 5, 1963 J. R. EVANS ETAL BREATHING APPARATUS 2 Sheets-Sheet 1 FiledFeb. 14, 1958' J. R. EVANS ETAL 3,076,454

Feb. 5, 1963 BREATHING APPARATUS 2 Sheets-Sheet 2 Filed F p b. 14, 1958United States Patent 3,076,454 BREATHING APPARATUS James R. Evans, LongBeach, and Leon Jones, Garden Grove, Calif., assignors toRobertshaw-Fulton Controls Company, Richmond, Va.. a corporation ofDelaware Filed Feb. 14, 1958, Ser. No. 715,458 4 Claims. (Cl. 128-142)This invention relates to breathing apparatus and more particularly toan arrangement whereby the likelihood of over-pressurization of abreathing mask is greatly reduced.

In prior devices of this type, a conduit was used to connect an oxygenregulator with the oronasal cavity of a breathing mask. The mask wasprovided with an inlet check valve and balanced exhalation valve whichled back to a relief valve in the conduit and was subject to thepressure in the conduit. Inhalation by the user would cause opening ofthe inlet valve and closing of theexhalation valve. Upon exhalation bythe user, the unbalanced pressure created would cause the inlet checkvalve to close and the exhalation valve to open. This would create anincreased pressure in the conduit and if the pressure became too great,the relief valve situated therein would operate to expel the excesspressure.

However, if the inlet check valve developed a leak, pressure could notbe built up across the check valve and accordingly, pressure could notbe built up across the exhalation valve and the user was therebyprevented from exhaling.

Also, if the regulator was subject to leakage, the pressure upstream ofthe check valve would build up continuously and prevent the properpressure differential inlet check valve on the mask of a breathingapparatus.

In the preferred embodiment of this invention, a fluid pressureregulator is connected to a face mask and controls the fluid flowthereto from a source of fluid under pressure. A differential pressureoperated exhalation valve is provided on the face mask and means isprovided for subjecting one side of the exhalation valve to apredetermined pressure to insure operation of the valve regardless ofthe operation of the regulator, thereby preventing lung damage uponregulator failure and eliminating the use of an inlet check valve in themask.

Other objects and advantages will become apparent from the followingdetailed description taken in connection with the accompanying drawingswherein:

FIG. 1 is a schematic illustration of a breathing apparatu-s;

FIG. 2 is a plan view of the regulator valve shown in FIG. 1, but on anenlarged scale;

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2 and having asmall cut-away portion; and

FIG. 5 is a schematic illustration of the regulator mask connection on areduced scale.

Referring more particularly to FIG. 1, the breathing apparatus includesa pressure reducing valve connected to a suitable source of oxygen underpressure (not shown) by a conduit 12. The reducing valve 10 may be ofany suitable form and serves to deliver oxygen at "ice a workablepressure to a breathing regulator 14 by means of a conduit 16. Theregulator 14 is here shown as mounted on a face mask 18.

Referring now more particularly to FIGS. 2, 3, and 4, the regulatorvalve 14 comprises a casing 20 having a hollow tubular inlet fitting 22extending from one side thereof. The casing 20 is also provided with anexternally threaded lower portion 24, on which a nut 26 is carried. Awall 27 of face mask 18 is compressed between nut 26 and casing 20 tosecure the casing 20 to the face mask 18. The inlet fitting 22 isadapted for connection to the conduit 16 (FIG. 1).

The inlet fitting 22 has a suitable filter 28 mounted therein, and isconnected by means of a passage 30 to a valve chamber 32 formed withinthe casing 20. The valve chamber 32 communicates with the face mask 18by means of a plurality of ports 34 which communicate with an opening 36in the bottom wall of the casing portion 24.

An annular valve seat 38 is formed on the casing 20 within the valvechamber 32 for cooperation with a flexible diaphragm valve member 40 forcontrolling fluid flow from the inlet passage 30 to the ports 34. Thevalve member 40 is secured at its periphery to the Wall of the casing 20by means of an annular retaining member 42 formed on the casing.

A passage 44 extends through the casing 20 from the inlet passage 30 andopens into the valve chamber 33 on the lower side of the diaphragm valvemember 40 to subject the lower side of the diaphragm valve member 40 toinlet fluid pressure. The passage 44 is provided with a chamber 46 inwhich a fitting 48 having a metering orifice therein is positioned. Withthis arrangement, the upper side of the valve member 40 is subjected tothe inlet fluid pressure within chamber 30, and the lower side of thevalve member 40 is subjected to the inlet fluid pressure by means ofpassage 44.

It will be apparent that the effective area of the valve member 40exposed to the inlet fluid pressure at the lower side thereof is greaterthan the exposed area of the upper side. This difference in areasubjected to inlet fluid pressure accordingly establishes a forcedifferential on the valve member 40 which normally tends to hold thesame in engagement with the seat 38.

The valve member 40 is moved out of engagement with the seat 38 topermit flow of fluid to the ports 34 and face mask 18 by venting thefluid pressure acting on the lower side thereof to reverse the forcedifferential acting on the valve member 40. To this end, a passage 50formed in the casing 20 extends from the valve chamber 33 at theunderside of the diaphragm valve member 40 and opens into a chamber 52formed in the casing 20 which communicates with the interior of the mask18 by means of a port 54.

A flexible diaphragm sensing element 56 is secured at its periphery tothe upper end of the casing 20 to enclose the chamber 52 and todefinethe upper wall thereof. The position of the diaphragm sensingelement 56 is influenced by the fluid pressure within the chamber 52.Accordingly, the chamber 52 is in communication with the mask 18, areduction in the pressure will occur within the chamber 52 when the userof the apparatus inhales causing the diaphragm 56 to flex downward. Thismovement of the diaphragm 56 in response to inhalation by the user isused to control the venting of the fluid pressure acting on theunderside of the valve member 40 to thus control opening of the valvemember 40.

A hollow fitting 58 has one end pressed within the end of the passage 50and the other end thereof projecting within the chamber 52 to define apilot valve seat. A pilot valve, indicated generally by the referencenumeral 60, is Cooperative with the end of the fitting 58 to controlfluid flow from the valve chamber 33 through the passage 59 to thechamber 52. The pilot valve 61) comprises a rigid lever arm 62 havingone end engageable with the diaphragm 56 and the other end thereof fixedto a block 64 overlying the fitting 53. One end of a strip 66 of sealingmaterial is secured to the underside of the block 64 and the other endof the strip 66 is .clamped to an extending and movable partition 68 ofthe casing 28 by means of a nut 70 tightened against the partition 68 bya screw 72 seated within a counterbore 73 in the casing portion 24. Aspring 7-; has one end attached to the block 64 and the other endthereof 'at- .tached to the nut 70 for biasing the block 64 downwardlyand the end of the lever arm 62 into engagement with the diaphragm 56.During assembly, the screw 72 is tightened to cause downward deflectionof the partition 62 will occur,-and the spring 74 will yield adjacentthe --nut 70 against its bias and move the block 64 out of engagementwith the fitting 58 to permit flow 'of fluid from the passage 50. Whenthe user exhales, the pressure in chamber 52 will increase to move thediaphragm 56 upwardly and allow the bias of spring 74 to close the-pilot valve 6t) .thusreestablis'hing the force differential on thevalve member 40 causing thesarne to engage its seat 38.

It hasbeen found that the chattering onvibra't-ion of the diaphragmvalve member 40 sometimes occurs due to the rapid pressure changes inchamber 33 upon opening and closing of the pilot valve 69. To providefor a more gradual pressure build-up or relief on the underside of thediaphragm valve member 46 during operation of the pilot valve 60, asurge chamber 76 having a metering orifice 77 is provided in the casingportion 24 in communicationwith the passage 44. It will be apparent thatupon flow of fluid from the valve chamber 33 as a result of opening ofthe pilot valve 68, the flow of fluid from the chamber 76 as determinedby the metering orifice 77 will reduce the rate of pressure drop within-the chamber 33. Likewise, the rate of pressure buildup within thechamber '33 will be decreased by'the pres- "sure build-up in the chamber76 when the pilot valve 60 "is closed.

When the regulator thus far described is used-at high --altitudes orunder low atmospheric pressure conditions,

it is'desired to establish a predetermined pressure within the maskzorhelmet 18 independently of inhalation on the part of the user to providepressure breathing. Ac-

cordingly, the regular valve is provided with means for maintaining apredetermined pressure within the mask or helmet 18 in accordance withthe surrounding atmospheric pressure. To this end, a cup-shaped member78 having'an upper inwardly extending flange 80 is clamped to the upperend of the casing 20 and to the periphery of the diaphragm 56 by meansof a cover 82 threaded on the upper end of the casing 2G in engagementwith a lower outwardly extending flange S1 of the member 78. The flange80 is provided with a cenextending through the wall thereof.

rality of ports 95 in the bottom wall of the member 78.

The valve member 86 is cooperative with the flange 89 to control thefluid pressure within the chamber 92. When the valve member 86 is in theposition shown in FIG. 3, the lip 90 is out of engagement with theflange and fluid pressure is vented from the chamber 92 to theatmosphere through a plurality of ports 96 in the cover 82. However, ifthe valve member 86 is moved toward the diaphragm 56, the lip will bemoved closer to the flange 80' to throttle the flow of fluid from thechamber 92 and increase the fluid pressure in the chamber 92.

An expansible bellows member 97 is provided for actuating the valvemember 86 relative to the flange 80. The bellows member 97 has one endsealed to the bottom --wall of the valve member 86 and the other endthereof sealed to the flange 98 of a cup-shaped member 106. The member100 is provided with a central conical recess or indentation 102 whichengages a flange 10.4 formed on one end of ascrew 106 threaded throughthe cover 82 in axial alignment with the bellows member 97. A

spring 108 is mounted in compression between the valve .member'86 andthe flange 98 within the bellows member -97 and-serves to bias thebellows member 97 and valve ,member '86 downward.

The bellows member 97 is evacuated and will expand in response to adecrease in atmospheric pressure to actuate the valve member 86 downwardto move'the lip -90-toward the flange 80. Thus, the bellows member 97will expandinrresponse to an increase in altitude to move .the lip.;9.0.t-oward engagement with the flange 80 to increase the fluid pressurewithin chamber 92.

Referring more particularly to FIG. 5, the oxygen regulator l'4 isconnected to the mask 18 in direct communication with oronasal cavity114. A pressure differential operated exhalation or outlet valve 116 isprovided on the mask 18 and has one side in communication with a tionbetween the fitting 120 and the mask wall 27. An-

other passage 126, whichextends perpendicular to passage 122 andcommunicates therewith is connected to chamber 92 through ports 95.Therefore, one side of the exhalation valve 116 is subjected to thepressure within chamber 92 by way of ports 95, passages 126, 122,fitting 120, and passage 118.

A relief valve, indicated generally by'reference numeral 128, ispositioned adjacent the regulator 14 on the inlet side thereof to ventfluid pressure from passage 122 when the fluid pressure'exceeds apredetermined value. To this-end,-a hollow'tubular casing is secured tocasing 20 and is provided with-a plurality of ports 132 A valve seatingring 134isflxed within the tubular casing 130'and is adaptedto-b'e-engaged byavalve member 136 which is slidably mounted on a guidestem fixed to the end wallof-the casing 130. A spring 138 encircles thestem and is mounted in compression between the end wall of the casing139 and the valve member 136 for biasing the Elve member 136 intoengagement with the seating ring It will be-apparent that a pressuredifferential will exist across the valve member 136 when the sameengages the seat therefor since one side of the valve member 136 issubjected to the oxygen pressure within the passage 122 and the otherside thereof is subjected to atmospheric pressure. As long as thepressure differential force on the valve member 136 is less than thebias of the spring 138, the valve member 136 will engage the seat. If,however, due to an increase in the fluid pressure in the passage 122,the pressure differential force becomes greater than the biasing forceof the spring 138, the valve member 136 will be moved out of engagementwith the seat to 'vent the excessive fluid pressure in passage 122 tothe atmosphere. This will allow the exhalation valve 116 to relieveexcess mask pressure.

In operation, when the apparatus is used at low altitudes or atrelatively normal atmospheric conditions, the bellows member 97will bein the contracted condition and the v'alve'member 86 will he in itsuppermost position wherein the lip 90 is out of engagement with theflange 80. In'this position of the valve member 86, fluid pressure isvented from the chamber 92 to the atmosphere, and the fluid pressurewithin the chamber 92 will be minimum and approximately atmospheric.

When the user of the apparatus inhales, a reduction in fluid pressurewithin chamber 52 will occur and the diaphragm 156' vwill be deflecteddownward under the influence of the fluid pressure within chamber 92.Such movement of-the diaphragm 56 will cause opening of the pilot valve160 as previously described to effect opening of valve member 40. Whenthe valve member 40 is thus opened, oxygen will be supplied to the mask18.

Since the chamber 52 communicates with the interior of the mask 18 bymeans of the port 54, exhalation on the part of theuser will increasethe fluid pressure within the chamber 52 to return the diaphragm 56 toits original posi-tionand allow bias of spring 74 to close pilot valve60 and valve member 40..

If a decrease in atmospheric pressure should occur, such as during anincrease in altitude, the bellows mernber 97 will expand to move thevalve member 86 downward-1y. This movement of valve member 86 willaccordingly position the lip 90 closer to the flange 80 to throttletheflow of fluid from the chamber 91 causing an increase in fluidpressure within the chamber 92.

The increased fluid pressure in chamber 92 will move the diaphragm 56downwardly and open the pilot valve 60 to effect opening of the valvemember 40 to cause oxygen flow to the mask 18. However, since thechamber 52 is in communication with the mask, the supply of oxygen tothe mask when the user is not inhaling will increase the pressure inchamber 52 causing -a pressure force to be exerted on the diaphragm 56in opposition to the fluid pressure acting on the upper side of thediaphragm 56. This build-up in the pressure within chamber 52 willcontinue until the pressure in chamber 52 equals the pressure in chamber92 at which point the diaphragm 56 will have returned to its originalposition and allow the bias of spring 74 to close the pilot valve 60 andvalve member 40.

It will be apparent that in operation in the above manner, the diaphragm56 serves as a pressure regulator to maintain a fluid pressure withinthe mask 18 as determined by the position of the bellows member 97.Also, since inhalation on the part of the user is effective to open thepilot valve 60 by establishing a pressure difierential on the diaphragm56, it will be apparent that the sensitivity of the device to inhalationis constant irrespective of the atmospheric pressure condition sensed bythe bellows member 97. This constant sensitivity is due to the fact thatthe fluid pressure in chambers 52, 92 is always substantially the same.Accordingly, when the user inhales, a similar pressure difference isestablished across the diaphragm 56 at pressure breathing conditions asis established at straight demand conditions. Thus, the device isoperative to etfect pressure breathing at low atmospheric pressureconditions without effecting the sensitivity of the device to inhalationand exhalation on the part of the user.

If it is desired to calibrate the response of the bellows member 97 to aparticular atmospheric pressure condition, the screw 106 may be rotatedto vary the axial position of the bellows member 97 and the valve member86 relative to the flange 80. Such positioning of the bellows 6 member97 will accordingly vary the pressure condition at which the lip engagesthe flange 80.

Since the oxygen regulator 14 is in direct communication with theoronasal cavity 114 of mask 18 and no inlet check valve is utilized, itis obvious that over-pressurization of the face mask 18 due to failureof an inlet check valve is eliminated. Also, since the pressuredifferential operated exhalation valve 116 is subject tothe pressure inchamber 92 which is controlled by aneroid valve member 86, breathing isnot impaired by the exhalation valve due to a regulator leakage orfailure on the downstream side thereof. Accordingly, failure of theregulator valve member 40 will not over-pressurize the face mask 18 andno lung damage will result therefrom. The only failure that could causeexcessive mask pressure in this instance would be that which causesexcessive pressure build-up in the chamber 92 and this is limited byrelief valve 128.

It is now apparent that the present apparatus has eliminated the use ofan inlet check valve and reduced the likelihood of over-pressurizationof a face mask, thus accomplishing the objects of the presentapplication.

While a single embodiment of this invention has been herein shown anddescribed, it is apparent to those skilled in the art that many changesmay be made in the construction and arrangement of parts withoutdeparting from the scope of the invention as defined in the appendedclaims.

We claim:

1. In a breathing apparatus for supplying fluid from a source of fluidunder pressure to a cavity in a breathing mask or the like; a hollowcasing, a flexible diaphragm dividing the interior of said casing into afirst chamber communicating with said cavity and a second chamber ventedto the atmosphere, inlet means on said casing adapted to be connected tosaid source of fluid under pressure, means in said casing defining amain passage and a pilot passage, both of said passages communicating atone end with said inlet means and at their respective other ends withsaid first chamber, valve means in said main passage responsive topressure in said pilot passage to open said main passage to permit theflow of fluid therethrough from said inlet means to said first chamberonly when the pressure at the inlet end of said main passage exceeds thepressure in said pilot passage by a selected pressure, normally closedpilot valve means in said pilot passage controlling the flow of fluidfrom said pilot passage into said first chamber, means for opening saidpilot valve means in response to flexing movement of said diaphragminduced by a reduction in pressure in said first chamber to a selectedpressure differential below the pressure in said second chamber,restricted orifice means in said casing placing said second chamber inconstant communication with said inlet means, ambient atmosphericpressure responsive means for regulating the rate of venting of saidsecond chamber in inverse proportion to the ambient atmosphericpressure, and means for venting said cavity when the pressure in saidcavity exceeds the pressure in said second chamber.

2. Apparatus as defined in claim 1 wherein said means for venting saidcavity comprises a differential pressure actuated valve member having afirst side exposed to the pressure within said cavity, conduit meansconnecting the opposite side of said valve member to said secondchamber, and pressure responsive relief valve means connected in saidconduit between said second chamber and said differential pressureactuated valve member.

3. Apparatus as defined in claim 1 wherein said valve means in said mainpassage comprises means defining an annular valve seat having a centralpassage therethrough in communication with said inlet means, a valveport disposed outwardly of said valve seat and communicating with saidfirst chamber, a flexible diaphragm valve member mounted in said casingfor movement into and out of 8 engagement with said valve seat andoperable when enmeans defining a surge'chamber in said pilot passagebegaged with said valve seat to block communication between said inletand said enlarged chamber, tween said central passage and said port,said pilot passage having an enlarged chamber therein having one wall Rfe n es Cited i the file 9f Patent defined by said diaphragm valvemember, the area of said 5 UNITED STATES PATENTS diaphragm valve memberexposed to said enlarged cham- 7 ..,597,039 Seeler May ZO, 1952 herbeing greater thanthe area of said central passage 2,755,799 Marty I y 6surrounded by'sa-id annular valve seat. v

e r 758,5 c p Au 14 9 6 4. Apparatus as defined in claim 3 furthercomprising 2,938,528 Schmitt A H ay 1960

1. IN A BREATHING APPARATUS FOR SUPPLYING FLUID FROM A SOURCE OF FLUIDUNDER PRESSURE TO A CAVITY IN A BREATHING MASK OR THE LIKE; A HOLLOWCASING, A FLEXIBLE DIAPHRAGM DIVIDING THE INTERIOR OF SAID CASING INTO AFIRST CHAMBER COMMUNICATING WITH SAID CAVITY AND A SECOND CHAMBER VENTEDTO THE ATMOSPHERE, INLET MEANS ON SAID CASING ADAPTED TO BE CONNECTED TOSAID SOURCE OF FLUID UNDER PRESSURE, MEANS IN SAID CASING DEFINING AMAIN PASSAGE AND A PILOT PASSAGE, BOTH OF SAID PASSAGES COMMUNICATING ATONE END WITH SAID INLET MEANS AND AT THEIR RESPECTIVE OTHER ENDS WITHSAID FIRST CHAMBER, VALVE MEANS IN SAID MAIN PASSAGE RESPONSIVE TOPRESSURE IN SAID PILOT PASSAGE TO OPEN SAID MAIN PASSAGE TO PERMIT THEFLOW OF FLUID THERETHROUGH FROM SAID INLET MEANS TO SAID FIRST CHAMBERONLY WHEN THE PRESSURE AT THE INLET END OF SAID MAIN PASSAGE EXCEEDS THEPRESSURE IN SAID PILOT PASSAGE BY A SELECTED PRESSURE, NORMALLY CLOSEDPILOT VALVE MEANS IN SAID PILOT PASSAGE CONTROLLING THE FLOW OF FLUIDFROM SAID PILOT PASSAGE INTO SAID FIRST CHAMBER, MEANS FOR OPENING SAIDPILOT VALVE MEANS IN RESPONSE TO FLEXING MOVEMENT OF SAID DIAPHRAGMINDUCED BY A REDUCTION IN PRESSURE IN SAID FIRST CHAMBER TO A SELECTEDPRESSURE DIFFERENTIAL BELOW THE PRESSURE IN SAID SECOND CHAMBER,RESTRICTED ORIFICE MEANS IN SAID CASING PLACING SAID SECOND CHAMBER INCONSTANT COMMUNICATION WITH SAID INLET MEANS, AMBIENT ATMOSPHERICPRESSURE RESPONSIVE MEANS FOR REGULATING THE RATE OF VENTING OF SAIDSECOND CHAMBER IN INVERSE PROPORTION TO THE AMBIENT ATMOSPHERICPRESSURE, AND MEANS FOR VENTING SAID CAVITY WHEN THE PRESSURE IN SAIDCAVITY EXCEEDS THE PRESSURE IN SAID SECOND CHAMBER.